If you're going to run a street tire and drive the truck; its fine. If you want to do burnouts, you'll kill it in a hurry. Modern 'rail shifted' manuals don't have the ability to shift as fast as a side shifted box (like a T10, Muncie, Toploader or 833/ 833OD). If you overshift it; it will bite you in the wallet. Tremec is really pushing to get past both the TKO and the T5; prices are going up for the OEM parts, and availability is going down. They'll be around longer than we will in some variation, because there isn't much choice LOL but you'll pay for it.
Go with the T5 if you've got street tires and a stock style clutch and you're looking to cruise. If you're going to be heavy handed; either get an ultra wide ratio 4 spd, a Doug Nash (Richmond 5 Spd) or a TKO. If youre doing a T56 swap; please do your homework on what you're going to use. You should probably get a 2.97 1st gear LT1 powered T56; but make sure you get the clutch release fork, the slave cylinder and the bracket to hold the Slave on the side of the trans with the donor. These parts are getting hard to find.